Open ClipArt and Inkscape do a pretty good job in promoting SVG. However quite a bit of content on the web that is called SVG, is actually only something that looks very much like SVG, but is not. "Not valid" breaks the principle of a standard. Therefore activities are started and some first code is hacked together to start changing that: http://openclipart.org/wiki/SVG_Testing#Previous_Tools

Next to code detecting errors based on DTDs and later also RNGs there's also code that gives the content coder advice, also to help workaround viewer implementation errors.

If you have some expertise in SVG or general XML, please invest a little bit of your valuable time.

Thanks